A ring buffer (42) records image data output from an ultrasound diagnosis device (1) in units of frames. A user identifies, on an image, occurrence of a target symptom while viewing a cross sectional image which is displayed in real time and inputs an end trigger (30) immediately after the symptom occurs. When the end trigger (30) is input, a system controller unit (20) instructs a recording controller unit (40) for recording of image data. The recording controller unit (40) sets a recording start time from the time when the end trigger (30) is input and extracts data corresponding to a period from the recording start time to the time when the end trigger (30) is input from the ring buffer (42) as data to be recorded. A data process is applied to the data to be recorded in a data processor unit (44) and recorded on a recording medium (46).
